题目链接:https://www.luogu.org/problemnew/show/P3128 菜 #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #define ll long long #define lson left, mid, rt<<1 #define rson mid+1, right, rt<<1|1 usin…

题目描述 Farmer John has installed a new system of N-1N−1 pipes to transport milk between the NN stalls in his barn (2 \leq N \leq 50,0002≤N≤50,000), conveniently numbered 1 \ldots N1…N. Each pipe connects a pair of stalls, and all stalls are connected t…

题意:一棵树,多次给指定链上的节点加1,问最大节点权值 n个点,n-1条边很容易惯性想成一条链,幸好有样例.. 简单的树剖即可!(划去) 正常思路是树上差分,毕竟它就询问一次.. #include<iostream> #include<cstring> #include<cstdio> using namespace std; inline int rd(){ ,f=;char c; :; +c-',c=getchar(); return ret*f; } <&l…

P3128 [USACO15DEC]最大流Max Flow 题目描述 Farmer John has installed a new system of N-1N−1 pipes to transport milk between the NN stalls in his barn (2 \leq N \leq 50,0002≤N≤50,000), conveniently numbered 1 \ldots N1…N. Each pipe connects a pair of stalls,…

P3128 [USACO15DEC]最大流Max Flow 题目描述 Farmer John has installed a new system of  pipes to transport milk between the  stalls in his barn (), conveniently numbered . Each pipe connects a pair of stalls, and all stalls are connected to each-other via path…

链接一下题目:luoguP3128 [USACO15DEC]最大流Max Flow(树上差分板子题) 如果没有学过树上差分,抠这里(其实很简单的,真的):树上差分总结 学了树上差分,这道题就极其显然了,不就是把每一条运输路线差分进去,那就是板子了啊. 树上差分还是很有用的,比较容易写,这种询问很少的题目去敲那么长(还容易出玄学错误)的树剖很浪费,用树上差分就很快了!(//...微笑...\\) 上一波代码: #include<iostream> #include<cstdlib>…

题目描述 Farmer John has installed a new system of  pipes to transport milk between the  stalls in his barn (), conveniently numbered . Each pipe connects a pair of stalls, and all stalls are connected to each-other via paths of pipes. FJ is pumping milk…

裸的树上差分 因为要求点权所以在点上差分即可 #include <cstdio> #include <algorithm> #include <cstring> using namespace std; ; ; ; ,u[MAXN*],v[MAXN*],first[MAXN],next[MAXN*]; int cf[MAXN]; ]; int n,k; void addedge(int ux,int vx){ cnt++; u[cnt]=ux; v[cnt]=vx; n…

题目:https://www.luogu.org/problemnew/show/P3128 倍增求 lca 也写错了活该第一次惨WA. 代码如下: #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; ; ],dep[maxn],s[maxn],mx; bool vis[maxn]; struct N{ int to,nx…

讲解: https://rpdreamer.blog.luogu.org/ci-fen-and-shu-shang-ci-fen #include <bits/stdc++.h> #define read read() #define up(i,l,r) for(register int i = (l);i <= (r);i++) #define down(i,l,r) for(register int i = (l);i >= (r);i--) #define traversal…